In 2003, Jon joined Bonhams as Global Director of Collectors' sales and he has since been responsible for many landmark auctions and world record prices. Highlights include: the British Airways Concorde auction, the Admiral Nelson Bicentenary sale, John Lennon' lyrics for Give Peace A Chance, Eric Clapton's Guitar Collection and the dress worn by the late actress Judy Garland in the role of Dorothy in the film The Wizard of Oz.

With over thirty years' experience in both auctioneering and dealing, Jon has a wide general knowledge of decorative arts and is an acknowledged expert in the areas of instruments of science and technology and marine decorative arts. He is the author of the reference work Nautical Antiques and Collectibles and is known to millions of people across the world as a specialist on the BBC's television programme The Antiques Roadshow, on which he has made regular appearances since it began in 1977.